Low emissivity glass (low-e glass) is glass having low emissivity, which is functional glass formed by coating the surface of glass with a particular layer to reflect solar radiation in summer and to store infrared light emitted from an indoor heater in winter, thereby realizing energy saving effects.
Conventionally, low emissivity glass is prepared by introducing oxygen into a chamber to create an oxygen atmosphere and depositing a thin oxide layer on a low emissivity layer using a metal target material in the oxygen atmosphere.
Thus, low emissivity glass prepared by such a conventional method includes a first dielectric layer formed of a metal oxide on a glass substrate, a low emissivity layer formed of silver (Ag) or the like, and a second dielectric layer formed of a metal oxide, which are sequentially deposited.
However, since such conventional low emissivity glass uses metal as a target material in an oxygen atmosphere upon deposition of the second dielectric layer on the low emissivity layer, as described above, a conductive metal contained in the low emissivity layer is also oxidized due to high oxygen partial pressure in the chamber, causing the low emissivity layer and the second dielectric layer to be mixed and form an unclear interfacial boundary therebetween. As a result, the low emissivity glass has remarkably increased emissivity and does not properly function.
In order to solve such problems, a primer layer of metallic nickel chrome is deposited on the low emissivity layer prior, and the dielectric layer is then deposited on the primer layer in an oxygen atmosphere, thereby preventing oxidation of a conductive metal contained in the low emissivity layer.
In this method, although oxidation of the conductive metal in the low emissivity layer is prevented to maintain low emissivity, the primer layer is additionally deposited on the low emissivity layer, thereby increasing the thickness of the thin metal layer and causing decrease in visible transmittance, complicating the overall process, and increasing manufacturing cost.